View Full Version : So how are you supposed to put the lid on the front brake reservoir?
I've just changed the oil, filter, plugs and brake fluid. It was an 'interesting' exercise and took rather longer than it should have I'm sure.
The main question I have havind done it is what's this flappy bit of black rubber under the lid of the front brake fluid reservoir. After I've finished changing fluid and bleeding how should I go about properly putting this back on. As it was I spilt brake fluid all over the place as it got displaced. For the time being I've just shoved the lid on but I'm sure that's wrong as it's now over the full line. But how to know how much to have in there before adding the lid?
Also having changed the fluid the brakes are as soggy or possibly worse than they were before (Baph - you remember how bad they were!). There is a lot of movement in the lever before it feels like they are biting and then it's soggily comes back to the bar if you pull hard enough. Is this normal for pointy breaks. Do I perhaps need braided lines or did I just fluff the fluid change?
Thanks in advance peeps.
/2mths
Sounds like a bad change, though you might still have a little air in the lines. So it might be adviseable to tie the leaver back over night and see what its like in the morning. If its still spongy in the morning you need to look at it again, if not then see what its like after a few hours released, if it sponges back up you probably have leak. In my case the master cylinder needed servicing too.
The lid should go on with the rubber cap pushed back so that it can expand over time and the fluid should be full to the max line on reservoir.
the_lone_wolf
01-06-07, 11:54 PM
As it was I spilt brake fluid all over the place as it got displaced.
can't help with the lid but you might want to get all the brake fluid off your paintwork before it removes it:smt103
petevtwin650
02-06-07, 08:50 AM
Braided hoses would no doubt improve the brakes, but as they were reasonable before the change I'd think you've got a little bit of air still lurking Andy.
Still as you get more experience with v twin engine braking you'll find you don't need the brakes anyway.:D
They stopped the bike ok but the lever feel before the change wasn't great. I think I need to get some more fluid (used all mine up doing my mate's bike up afterwards) and top up to try bleeding and then top up the reservoir correctly.
I understand about the engine braking but I would like to be nice to my rear tyre and chain as they aren't cheap either :-)
Not sure whether I'm answering the question you want but its possible that the black rubber 'thing' has extended slightly. It happend to me when I changed my fluid and I ended up with the fluid overflowing when I put the rubber back in. It should be fairly compressed with a flat bottom. Have a play and you'll see what I mean.
Andy, you probably had air in the system somewhere (probably in the master cylinder) before, and it sounds like you've got more of it now!
Personally, at that stage, I'd drop the fluid out & start again. I start from the bottom using a MityVac & push fluid up. Watch the reservoir whilst you're doing this, as you want to stop when the fluid appears and top it up a little from the top end.
Are you sure your bleed nipples are torqued up properly, and did you put some PTFE tape around them before you put them back in? Could be an air leak here.
If you've done all that, cable tie the lever & leave it overnight, it does magical things when the brake pixies come out to play.
As for the little rubber cap inside the reservoir, that's to help the seal stay tight. Pop that in (right way up) & screw the lid on, then put the retaining metal on & screw that in place. Worth noting what Andyb said, if the bit of rubber has got out of shape, it won't do it's job properly, so have a fiddle with this too.
Should be job done :)
northwind
02-06-07, 03:03 PM
It's not a question of getting out of shape, that's what it's supposed to do, it's a diaphragm- keeps fresh air out, when fluid volumes drop it pulls the diaphragm downwards, avoiding a buildup of pressure or letting new moist air in. Some people like to pre-expand it to reduce the volume of air to a minimum, but I don't think that's really needed. All you have to do is pop it back to the starting position though, like the others have said, just in a nit-picky mood ;) It'll draw back down as fluid displaces into the calipers (as the pads wear)
Flamin_Squirrel
02-06-07, 03:30 PM
Are you sure your bleed nipples are torqued up properly, and did you put some PTFE tape around them before you put them back in? Could be an air leak here.
Never heard of anyone using PTFE tape. Gonna put my head on the block and say it's not needed :cool:
northwind
02-06-07, 03:35 PM
PTFE tape can be handy, stops fluid from leaking down through the thread while you're bleeding, which is good with pressure bleeders. Can also compensate for damaged threads, and I suspect may help prevent seized nipples. And you don't want seized nipples :) But not neccesary at all.
One other thing Northwinds reply reminded me of. Unless you have replaced the pads you should leave some room in the resevoir for when you do replace em, or top the fluid up whilst the pads are pushed fully back, or be prepared for more fluid spillage when you do fit new ones. After you've pushed the pads back and replenished the fluid, don't forget to pump the brake lever until the pads once again bite on the pads.Many a bleeder has had a moment after forgetting to do that.
dirtydog
02-06-07, 07:48 PM
After you've pushed the pads back and replenished the fluid, don't forget to pump the brake lever until the pads once again bite on the pads.Many a bleeder has had a moment after forgetting to do that.
:-dd :-dd
Guilty of that one car and bike!
:oops: :oops: :oops:
kcowgergmm
03-06-07, 02:16 AM
is there any good tool that can be used to aid in the process of changing brakefluid and bleeding the lines
northwind
03-06-07, 02:52 AM
Thee big syringe. Mityvac's a nice piece of work but I prefer the big syringe, works brilliantly- I hate bleeding brakes, I'm rubbish at it, but this just makes it easy, and fast.
Never heard of anyone using PTFE tape. Gonna put my head on the block and say it's not needed :cool:
Pretty much as Northy says, not needed, but that doesn't stop me using it every time I take the bleed nipples out of the calipers.
I'd prefer the safety of knowing nothings going to go wrong (again, re: northy) for the tiny cost of it. I use PTFE tape for lots of things anyway, so I always have some kicking around.
Thee big syringe. Mityvac's a nice piece of work but I prefer the big syringe, works brilliantly- I hate bleeding brakes, I'm rubbish at it, but this just makes it easy, and fast.
How big is your syringe Northwind? Any idea what the fluid capacity of the front brake and line up to the reservoir is on a curvy. I got a 30 ml syringe - is that big enough to fill the brake cylinder and line up to the res?
I've heard about the tying the brake lever back thing before. What does that actually do?
When I used to do the brakes on cars I used to get the missus to slowly depress the brake pedal while she counted out loud so that I could release and tighten the bleed screw. When the issuing fluid was bubble free the particular brake line was free of air. Is air more likely to get trapped in a bike brake line?
northwind
03-06-07, 12:43 PM
Don't know really. It's pretty big :) 100ml maybe.
Red ones
03-06-07, 02:00 PM
I lost interest as soon as someone mentioned putting tape on your nipples!
I lost interest as soon as someone mentioned putting tape on your nipples!
LOL! and I expected a bit more comeback when I asked Northwind how big his thingy was.. :smt046
northwind
03-06-07, 02:52 PM
I just checked, and mine holds 70mm of the fluid of your choice ;)
Wow folks some really good stuff in there (I might see if I can draw it together and draft a FAQ type thing). I think I need to go over my breaks from scratch again. Also do some learning about bleading\refreshing.
Thankyou again.
+1 for using a syringe. Tried it after Northwind suggested it and managed to bleed brakes OK at the first attempt and I'd never blead brakes beofre in my life.
How do you use the syringe?
Or would that be better put "how is the syringe used"?
is there any good tool that can be used to aid in the process of changing brakefluid and bleeding the lines
Me!
one 8mm spanner, a length of plastic hose, a bottle or recepticle, and the correct technique.
I bled Grinchs new lines with less than 250ml fluid. No syringes, or mityvacs or anything like that.
Yep he did... And after that I did the same with my back brake. Just the only difference was that I took the brakes off to make it easier for me to get to the nipple and see the pistions move.
Me!
one 8mm spanner, a length of plastic hose, a bottle or recepticle, and the correct technique.
I bled Grinchs new lines with less than 250ml fluid. No syringes, or mityvacs or anything like that.
That's how I was thinking of doing it - like I have done many times before with many cars. I was just wondering if there was anything particularly difficult about a bike's brake system? Like, for example, are the line bores bigger and hence letting air bubbles trickle back up the line?
Anyway, to the syringe users: where do you get the big ass syringes from? I assume that you need to fill the cylinder and line up to th reservoir in one injection?
Me!
one 8mm spanner, a length of plastic hose, a bottle or recepticle, and the correct technique.
I bled Grinchs new lines with less than 250ml fluid. No syringes, or mityvacs or anything like that.
That's how I've always done it and how I do it. I want to know how to do that properly. My understanding is (if you have two people)...
* Slight pressure on brake lever
* Open bleed nipple (with tube attached taking old fluid off to recepticle)
* Brake lever is slowly squeezed
* As lever reaches end of travel bleed nipple is closed
* Repeat till fluid level in reservoir is at lower level
* Top up reservoir
* Repeat till new fluid is being bled
* Top reservoir up and job done
* (Might be some final bleed trickery people like to do?)
That's how I've always done it and how I do it. I want to know how to do that properly. My understanding is (if you have two people)...
* Slight pressure on brake lever
* Open bleed nipple (with tube attached taking old fluid off to recepticle)
* Brake lever is slowly squeezed
* As lever reaches end of travel bleed nipple is closed
* Repeat till fluid level in reservoir is at lower level
* Top up reservoir
* Repeat till new fluid is being bled
* Top reservoir up and job done
* (Might be some final bleed trickery people like to do?)
Almost the same as me, but i will leave the nipple open with the levr to the bar about a second (or counting to 2 in my head before closing the nipple then releasing the lever). If you use clear tubing, you can see that the fluid is still moving at that time. I also, when fitting new line, squeeze the lever and undo the banjos like the bleed nipples, to get flid down the lines at least.
I will also bleed the master cylinder in the same way genlte squeeze on lever, open and close the banjo. Job done.
The golden rule is, Never release the lever with ya nipples open! (fnarr fnarr)
I will admit though, it took me a long while to perfcet the technique and was condisering Mityvacs etc.
northwind
04-06-07, 04:15 PM
My syringe cost £2 and I can bleed a system from dry to fixed in about 5 minutes (took a bit longer to do Scooby Drew's as the nipples are a different size, pain in the bum that), so, I'll keep on doing that :) But I'd be the first to admit the reason I hate doing it the traditional way is that I suck at it. So to speak.
northwind
04-06-07, 04:28 PM
Or would that be better put "how is the syringe used"?
I keep meaning to do a video. Might do next time, I want to do the fronts soon. Dead simple though... You just need your syringe and some suitably sized hose. I got mine together on Ebay for £2, which is daft since the parts blatantly cost about 20p, but anything for a quiet life.
Drain brakes of old fluid. Fill syringe with about 50mm of new fluid. Attach to one of the caliper ipples, and push- the fluid will push up the lines, displacing the air. Obviously you have to do this for both calipers- if you have a 1 down, 1 across brake line setup start from the last one in line.
That'll give a decent but imperfect bleed after one go, usually, maybe 2 minutes work. Now, you've got a choice, you can either push it back down from the lever, leaving the syringe attached- conventional bleeding really. This'll clear any persistant bubbles in the caliper. Or, you can just carry on pushing fluid up, sucking it out of the reservoir if it gets full, and repeating- but I find it best to use a mix of the two. Push up, push down, push back up. Repeat if neccesary, but it's not usually.
Things to watch for... Obviously, the hose can pop off the nipple, so hold it in place. If you're not careful you can overfill the reservoir without noticing. And if you do it too much, or too fast, you'll end up with microbubbles in the fluid same as if you pump the lever too fast when bleeding normally- needs to be left to settle if this happens. And if the nipple's too loose the fluid will escape past the threads.
What's quite nice is that you can avoid ever having any "free" fluid, no open jars etc- you can use the syringe as a receptacle to push fluid into when bleeding from the lever, it'll expand to take it.
Thanks northwind, that's great info. I'll be keeping an eye out for giant syringes :-) and if I find one I'll give that a go. I also need to find a quantity of hose. It should be such cheap stuff but people always want silly money for it.
northwind
04-06-07, 06:12 PM
Honestly, I think you'd be better learning to do it "properly", frees you up from the need for the tool... But I know my limits, if it's hard to do- give up and do something else :)
http://cgi.ebay.co.uk/trials-motorcross-enduro-clutch-brake-bleed-kit-etc_W0QQitemZ330125349134QQihZ014QQcategoryZ25644Q QrdZ1QQcmdZViewItem
Yes, I know, far too expensive for what you get. But still, I figured I could either buy one at an inflated price, or spend half an hour going to a veterinary goods shop, or maybe a really big chemist, and hunting around for one in order to save a couple of quid.
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